Drive slow, save money -- really

You've probably seen a million lists of gas-savings tips recently (yes, Yahoo! has run our share, we admit). One of the suggestions is always to drive slower or drive the speed limit.

So someone finally asked Salon's resident eco-expert if it's really true that driving slower saves gas. After all, won't you use more gas because it takes longer to get to your destination if you drive slower?

Not so fast, speedfreak. Pablo Päster says the savings is real, and it's due to aerodynamic drag, which trumps the time savings of speeding down the freeway.

Basically "slower speed equals less drag," and you can reduce fuel consumption by 20 percent if you slow down from 70 mph to 60 mph.

For comparison, if you drive 10 mph faster over a 30-mile commute, you'll only shave four minutes off the total driving time. The savings doesn't extend forever, so don't bother creeping along the fast lane at 5 mph.

Salon mentions another great way to improve aerodynamics: Remove the roof rack. Our friends at the Rocky Mountain Institute estimate that you can save 15 to 30 gallons of gas per year if you leave off the rack just half the time. Most folks don't need it up there all 365 days anyway.

Slow down, ditch the rack, and save some bucks. It's true -- it's that easy.